1. Field of the Invention
The present invention relates to an attraction state inspection device that inspects the attraction state of a part attracted by a nozzle, and a surface mounting apparatus and a part test device provided with the attraction state inspection device.
2. Description of the Background Art
For example, a large number of surface mounting apparatuses and part inspection devices have been provided as apparatuses having a mechanism for handling parts such as electronic parts. These apparatuses are provided with attraction nozzles for holding the electronic parts. The attraction nozzles attract the lower surface of the parts at the lower distal end thereof and hold the parts. Further, a plurality of the attraction nozzles are carried on a head unit for effectively conveying the parts from a part supply source to a target position. The head unit conveys a plurality of parts to the target position in a state in which the parts are held by the attraction nozzles. Positioning of the parts to the target positions is performed by releasing the parts held by the attraction nozzle at the target position for each part. Therefore, in order to increase the positioning accuracy, it is important to examine the attraction state of the part attracted by the attraction nozzle prior to positioning and position the part with consideration for the attraction state. Accordingly, the surface mounting apparatus and part test device are provided with an attraction state inspection device for inspecting the attraction state.
Such an attraction state inspection device is described, for example, in Japanese Patent Application Laid-open No. 2007-287986. In this conventional device, a plurality of attraction nozzles are held by a nozzle holder that can rotate about an axial line extending in the up-down direction, and a reflector is disposed on the axial line. In other words, a plurality of attraction nozzles are disposed so as to surround the reflector. A CCD (Charge Coupled Device) camera and a LED (Light Emitting Diode) are provided at one side of the nozzle group of such a configuration. A two-dimensional image of an electronic part attracted to the distal end of the attraction nozzle is picked up with the CCD camera by using light reflected by the reflector, from the irradiation light from the LED. The attraction state of the electronic part is inspected on the basis of the image pickup results.
In the above-described attraction state inspection device, the light reflected by the reflector is reflected from the reflector side to the part facing the CCD camera and a silhouette image of the part is formed. The attraction state of the part attracted by the nozzle can be recognized on the basis of the silhouette image. However, since the LED is disposed on the CCD camera side, the following problems are encountered.
Thus, a portion of the irradiated light from the LED is reflected by the part that is the inspection object (part to be inspected) and enter the CCD camera. Therefore, the contrast of the part and background in the image picked up by the CCD camera decreases, thereby causing the decrease in recognition accuracy. In order to resolve this problem, an optical filter apparently can be disposed between the CCD camera and the LED. However, with such a method for resolving the problem, the size and cost of the device are increased. Furthermore, a large number of LEDs should be arranged in order to compensate the decrease in the quantity of light caused by the insertion of the optical filter. In addition, when a configuration is used in which the irradiation unit such as a LED is provided on the CCD camera side, the irradiation unit should be disposed so as to avoid the optical path of the light falling on the CCD camera. In such a case, the quantity of light is decreased, or the irradiation unit is increased in size in order to compensate such a decrease in the quantity of light.